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Industrial waste treatment at Trans World Airlines overhaul base

page 194

Industrial Waste Treatment at
Trans World Airlines Overhaul Base
GEORGE C. HIGGINS, Project Engineer
Burns and McDonnell Engineering Company
Kansas City, Missouri 64141
INTRODUCTION
From the first day of operation, the personnel of Trans World Airlines overhaul complex, located at Mid-Continent International Airport, havebeen faced
with the task of providing adequate treatment for the industrial waste from this
installation. In the beginning, the wastes requiring treatment were: 1) that from
a plating shop consisting of cyanide and chrome streams, and 2) that from aircraft maintenance. As the site continued to expand, the quantity and type of
wastes increased. The increase in petroleum waste from the engine overhaul process necessitated a previous treatment plant expansion to treat this waste. Presently, additional capacity is under construction to provide treatment for the plating shop expansion, new hangar facilities and increased fleet size. The new
facilities will be adequate until the jumbo jet and supersonic planes enter the
fleet. Besides the preceding factors necessitating additional treatment capacity,
an additional item suggesting a need for an increase was Trans World Airlines desire to provide an acceptable effluent -- one that will meet the stream quality
standards which regulatory agencies are proposing.
At present there are four distinct waste streams requiring treatment from the
industrial complex which comprises and overhaul facility. The streams are 1)
alkaline-cyanide, 2) acid-chrome, 3) industrial-petroleum, and 4) sanitary; however, only the first three will be discussed. The existing treatment facilities are
located in the same vicinity with the controls housed in two interconnecting
buildings adjacent to the treatment units. However, there is a distinct line of
demarcation between the two areas where wastes are being treated. The metal
finishing wastes are centered at the south end of the site with the petroleum wastes
located at the north end.
METAL FINISHING WASTES
The plating wastes originate in the plating shop area of the engine overhaul
building. Complete stripping and plating operations for the aircraft's components and engines are carried out here which give rise to two entirely different and
complex waste streams. One is the alkaline stream containing all cyanide and
alkaline wastes. The other is the acid stream containing all chrome, acids and
other heavy metal wastes. Each waste as it reaches the plant enters a retention
basin which acts as a flow and concentration equalization basin. The waste is
then pumped from these units at a constant rate to the process basins (Figure 1).
The cyanide bearing waste is destroyed by the alkaline-chlorination process
which oxidizes the cyanide to carbon dioxide and nitrogen. Liquid caustic soda
and chlorine are the chemicals used. The chemicals are first added to the waste
in the two-minute basin in a ratio of 7 lbs of chlorine for each lb of free cyanide
(CN~) and 1.25 lb of caustic soda per lb of chlorine. From here the waste overflows into the two-hour basin where additional chlorine and caustic soda are added
to complete the cyanide oxidation. Part of the effluent from the two-hour basin
- 194 -

Industrial Waste Treatment at
Trans World Airlines Overhaul Base
GEORGE C. HIGGINS, Project Engineer
Burns and McDonnell Engineering Company
Kansas City, Missouri 64141
INTRODUCTION
From the first day of operation, the personnel of Trans World Airlines overhaul complex, located at Mid-Continent International Airport, havebeen faced
with the task of providing adequate treatment for the industrial waste from this
installation. In the beginning, the wastes requiring treatment were: 1) that from
a plating shop consisting of cyanide and chrome streams, and 2) that from aircraft maintenance. As the site continued to expand, the quantity and type of
wastes increased. The increase in petroleum waste from the engine overhaul process necessitated a previous treatment plant expansion to treat this waste. Presently, additional capacity is under construction to provide treatment for the plating shop expansion, new hangar facilities and increased fleet size. The new
facilities will be adequate until the jumbo jet and supersonic planes enter the
fleet. Besides the preceding factors necessitating additional treatment capacity,
an additional item suggesting a need for an increase was Trans World Airlines desire to provide an acceptable effluent -- one that will meet the stream quality
standards which regulatory agencies are proposing.
At present there are four distinct waste streams requiring treatment from the
industrial complex which comprises and overhaul facility. The streams are 1)
alkaline-cyanide, 2) acid-chrome, 3) industrial-petroleum, and 4) sanitary; however, only the first three will be discussed. The existing treatment facilities are
located in the same vicinity with the controls housed in two interconnecting
buildings adjacent to the treatment units. However, there is a distinct line of
demarcation between the two areas where wastes are being treated. The metal
finishing wastes are centered at the south end of the site with the petroleum wastes
located at the north end.
METAL FINISHING WASTES
The plating wastes originate in the plating shop area of the engine overhaul
building. Complete stripping and plating operations for the aircraft's components and engines are carried out here which give rise to two entirely different and
complex waste streams. One is the alkaline stream containing all cyanide and
alkaline wastes. The other is the acid stream containing all chrome, acids and
other heavy metal wastes. Each waste as it reaches the plant enters a retention
basin which acts as a flow and concentration equalization basin. The waste is
then pumped from these units at a constant rate to the process basins (Figure 1).
The cyanide bearing waste is destroyed by the alkaline-chlorination process
which oxidizes the cyanide to carbon dioxide and nitrogen. Liquid caustic soda
and chlorine are the chemicals used. The chemicals are first added to the waste
in the two-minute basin in a ratio of 7 lbs of chlorine for each lb of free cyanide
(CN~) and 1.25 lb of caustic soda per lb of chlorine. From here the waste overflows into the two-hour basin where additional chlorine and caustic soda are added
to complete the cyanide oxidation. Part of the effluent from the two-hour basin
- 194 -